This is a note to let you know that I've just added the patch titled
brd: mark as nowait compatible
to the 6.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
brd-mark-as-nowait-compatible.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 67205f80be9910207481406c47f7d85e703fb2e9 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@xxxxxxxxx>
Date: Wed, 15 Feb 2023 16:43:47 -0700
Subject: brd: mark as nowait compatible
From: Jens Axboe <axboe@xxxxxxxxx>
commit 67205f80be9910207481406c47f7d85e703fb2e9 upstream.
By default, non-mq drivers do not support nowait. This causes io_uring
to use a slower path as the driver cannot be trust not to block. brd
can safely set the nowait flag, as worst case all it does is a NOIO
allocation.
For io_uring, this makes a substantial difference. Before:
submitter=0, tid=453, file=/dev/ram0, node=-1
polled=0, fixedbufs=1/0, register_files=1, buffered=0, QD=128
Engine=io_uring, sq_ring=128, cq_ring=128
IOPS=440.03K, BW=1718MiB/s, IOS/call=32/31
IOPS=428.96K, BW=1675MiB/s, IOS/call=32/32
IOPS=442.59K, BW=1728MiB/s, IOS/call=32/31
IOPS=419.65K, BW=1639MiB/s, IOS/call=32/32
IOPS=426.82K, BW=1667MiB/s, IOS/call=32/31
and after:
submitter=0, tid=354, file=/dev/ram0, node=-1
polled=0, fixedbufs=1/0, register_files=1, buffered=0, QD=128
Engine=io_uring, sq_ring=128, cq_ring=128
IOPS=3.37M, BW=13.15GiB/s, IOS/call=32/31
IOPS=3.45M, BW=13.46GiB/s, IOS/call=32/31
IOPS=3.43M, BW=13.42GiB/s, IOS/call=32/32
IOPS=3.43M, BW=13.39GiB/s, IOS/call=32/31
IOPS=3.43M, BW=13.38GiB/s, IOS/call=32/31
or about an 8x in difference. Now that brd is prepared to deal with
REQ_NOWAIT reads/writes, mark it as supporting that.
Cc: stable@xxxxxxxxxxxxxxx # 5.10+
Link: https://lore.kernel.org/linux-block/20230203103005.31290-1-p.raghav@xxxxxxxxxxx/
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/block/brd.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -412,6 +412,7 @@ static int brd_alloc(int i)
/* Tell the block layer that this is not a rotational device */
blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
+ blk_queue_flag_set(QUEUE_FLAG_NOWAIT, disk->queue);
err = add_disk(disk);
if (err)
goto out_cleanup_disk;
Patches currently in stable-queue which might be from axboe@xxxxxxxxx are
queue-6.2/io_uring-handle-tif_notify_resume-when-checking-for-task_work.patch
queue-6.2/brd-return-0-error-from-brd_insert_page.patch
queue-6.2/fs-hfsplus-fix-uaf-issue-in-hfsplus_put_super.patch
queue-6.2/block-don-t-allow-multiple-bios-for-iocb_nowait-issue.patch
queue-6.2/sbitmap-correct-wake_batch-recalculation-to-avoid-po.patch
queue-6.2/blk-mq-avoid-sleep-in-blk_mq_alloc_request_hctx.patch
queue-6.2/io_uring-add-reschedule-point-to-handle_tw_list.patch
queue-6.2/ublk_drv-remove-nr_aborted_queues-from-ublk_device.patch
queue-6.2/io_uring-remove-msg_nosignal-from-recvmsg.patch
queue-6.2/brd-check-for-req_nowait-and-set-correct-page-allocation-mask.patch
queue-6.2/io_uring-mark-task-task_running-before-handling-resume-task-work.patch
queue-6.2/blk-mq-fix-potential-io-hung-for-shared-sbitmap-per-.patch
queue-6.2/blk-mq-wait-on-correct-sbitmap_queue-in-blk_mq_mark_.patch
queue-6.2/block-clear-bio-bi_bdev-when-putting-a-bio-back-in-the-cache.patch
queue-6.2/io_uring-fix-fget-leak-when-fs-don-t-support-nowait-buffered-read.patch
queue-6.2/ublk_drv-don-t-probe-partitions-if-the-ubq-daemon-is.patch
queue-6.2/trace-blktrace-fix-memory-leak-with-using-debugfs_lo.patch
queue-6.2/io_uring-audit-don-t-log-ioring_op_madvise.patch
queue-6.2/io_uring-rsrc-disallow-multi-source-reg-buffers.patch
queue-6.2/x86-fpu-don-t-set-tif_need_fpu_load-for-pf_io_worker.patch
queue-6.2/io_uring-replace-0-length-array-with-flexible-array.patch
queue-6.2/blk-cgroup-dropping-parent-refcount-after-pd_free_fn.patch
queue-6.2/block-be-a-bit-more-careful-in-checking-for-null-bdev-while-polling.patch
queue-6.2/block-use-proper-return-value-from-bio_failfast.patch
queue-6.2/block-fix-io-statistics-for-cgroup-in-throttle-path.patch
queue-6.2/block-ublk-check-io-buffer-based-on-flag-need_get_da.patch
queue-6.2/io_uring-use-user-visible-tail-in-io_uring_poll.patch
queue-6.2/blk-cgroup-synchronize-pd_free_fn-from-blkg_free_wor.patch
queue-6.2/sbitmap-remove-redundant-check-in-__sbitmap_queue_ge.patch
queue-6.2/io_uring-poll-allow-some-retries-for-poll-triggering-spuriously.patch
queue-6.2/block-sync-mixed-merged-request-s-failfast-with-1st-.patch
queue-6.2/blk-mq-remove-stale-comment-for-blk_mq_sched_mark_re.patch
queue-6.2/brd-mark-as-nowait-compatible.patch
queue-6.2/blk-iocost-fix-divide-by-0-error-in-calc_lcoefs.patch
queue-6.2/s390-dasd-fix-potential-memleak-in-dasd_eckd_init.patch
queue-6.2/blk-mq-correct-stale-comment-of-.get_budget.patch
queue-6.2/io_uring-add-a-conditional-reschedule-to-the-iopoll-cancelation-loop.patch
queue-6.2/block-bio-integrity-copy-flags-when-bio_integrity_pa.patch
